It has been more than two decades since the structure-to-function paradigm was challenged by the discovery that intrinsically disordered proteins (IDPs), that lack fixed 3D structures, have significant biological functions [1]}, [2]}. Yet, many questions relating the primary sequence to biological function remain open [3]}, [4]}. IDPs are known to participate in many cellular functions [5]}, [6]} and to remain unstructured even in the crowded environment of the cell [7]}. IDPs can become structured or remain unstructured while participating in protein-protein interaction [8]}. Either way, the interaction can be very strong while fully retaining the IDP's structural disorder [9]}.
